Rentech Moves on Its PolyGeneration Strategy: Fertilizer, FT Fuels and Power

7 November 2005

Rentech, a Fischer-Tropsch process company, is acquiring a Royster-Clark nitrogen fertilizer plant in East Dubuque, Illinois, in a $50-million deal that will provide Rentech with a platform for its polygeneration strategy: the co-production of fertilizer, Fischer-Tropsch synthetic fuels and electric power via coal gasification.

Rentech plans to convert the natural-gas fertilizer plant to coal-fed gasification using Illinois coal. The conversion calls for two gasification trains and a spare, standby gasifier at the site to process 5,200 tons per day of coal, the commercial equivalent capacity of a 650 megawatt Integrated Gasification Combined Cycle (IGCC) power plant.

Rentech’s CTL Poly-Generation Vision

The new expanded gasification process will generate the synthesis gas necessary to increase the nitrogen fertilizer production to more than 900 tons per day and is projected to produce an estimated 87 million gallons per year of Fischer-Tropsch (FT) fuels as well as surplus electricity.

Rentech estimates that it will take approximately three and one-half years to convert the plant from natural gas to coal feedstock. Rentech may make available a portion of the Fischer-Tropsch fuels to the Department of Defense Clean Fuels Program, regional metropolitan transit systems and area farming cooperatives under long term contracts. In addition, RDC has already begun discussions with local electric cooperatives for long term power sales.

When and if complete, Rentech believes the plant will produce the first commercial scale volume of Fischer-Tropsch fuels, including jet fuel, from coal in the United States. Moreover, the conversion of the RCI facility from natural gas to coal could catalyze several additional conversion efforts.

The conversion will also address issues within the domestic nitrogen fertilizer industry which has suffered from high volatile natural gas prices since 1999. By co-producing nitrogen fertilizer, FT fuels and electricity from coal-derived synthesis gas, Rentech will be maximizing the thermal efficiency of the facility and utilizing the BTU output of the plant with the highest value products while in turn improving the profitability of the overall process.

This is the way things will have to go, as natural gas production in North America continues to fall off. Integrated production of fertilizer, FT liquids, and power is definitely an efficient way to use coal. About the only major way to improve it--if they're not already planning to do it--is to produce a pure CO2 waste stream and sell it for EOR operations. Anybody know if there are old oil fields in the vicinity?

Failing that, the other way they could address the CO2 issue and make the project even "greener" would be to couple it with wind farms. They'd use surplus power when the wind is blowing to produce H2 and O2 by electrolysis of water. The O2 would be used for gasification of coal, and the hydrogen would be used to reduce CO2 emissions (in both senses of "reduce") and enhance production of synthesis gas.

This is kind of a mixed bag. Because of slightly higher thermal efficiency the combined energy value of electricity and liquid fuel per ton of CO2 should be higher than from separate specialty plants. That's the good part but the flip side is that all that carbon was once locked out of the atmosphere as coal. There has to be some kind of financial incentive to go the extra mile to capture the CO2 emitted by the plant, remembering that more CO2 is emitted outside the plant when the fuel is used.

Given the energy converted to heat in the gasification and F-T processes, you can bet that the CO2 impact is considerably worse than natural gas or petroleum. The hydrogen is largely split from water, and that means carbon converted to CO2.

The polygeneration might redeem this somewhat, but I find it more interesting that the plant is located in Danville, in the middle of farm country. There's a lot of surplus biomass being generated all around it. If the plant could be modified to handle e.g. baled corn stover (or just fed charcoal produced from stover), it could provide a new market for the local farmers and reduce net CO2 emissions.

The ideal situation would be for the plant to run entirely on charcoal and close the energy loop with the farms it supplies, while producing electricity and motor fuel.

Biomass is purely fossil fuel based especially corn residue. The most sustainable means of producing ammonia is through hydrogen generation via nuclear or any of the renewable sources like wind and solar. The hydrogen can then be combined with atmospheric nitrogen and bingo - NH3.